<!DOCTYPE html>
<html lang="zh_CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript" src="../jquery-3.5.1.js"></script>
    <script type="text/javascript">

        $(function () {

                        // 批量操作单选
                        $("#single").val(["sin3"]);
            /*  $(":radio").val(["radio2"]);
           /*   // 批量框的选中状态
            $(":checkbox").val(["checkbox3","checkbox2"]);
            // 批量操作多选的下拉框选中状态
            $("#multiple").val(["mul2","mul3","mul4"]);
            // 操作单选的下拉框选中状态
            $("#single").val(["sin2"]);
*/
            // $("#multiple,#single,:radio,:checkbox").val(["radio2","checkbox1","checkbox3","mul1","mul4","sin3"]);
        });

    </script>
</head>
<body>
<body>
单选：
<input name="radio" type="radio" value="radio1" />radio1
<input name="radio" type="radio" value="radio2" />radio2
<br/>
多选：
<input name="checkbox" type="checkbox" value="checkbox1" />checkbox1
<input name="checkbox" type="checkbox" value="checkbox2" />checkbox2
<input name="checkbox" type="checkbox" value="checkbox3" />checkbox3
<br/>

下拉多选 ：
<select id="multiple" multiple="multiple" size="4">
    <option value="mul1">mul1</option>
    <option value="mul2">mul2</option>
    <option value="mul3">mul3</option>
    <option value="mul4">mul4</option>
</select>
<br/>

下拉单选 ：
<select id="single">
    <option value="sin1">sin1</option>
    <option value="sin2">sin2</option>
    <option value="sin3">sin3</option>
</select>
</body>
</body>
</html>